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Objectives  Today, compact discs are still the most convenient source popular mass data storage  The downfall of this technology is that data can be easily lost or damaged  Improving the durability of a CD would make this technology more reliable

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Background of Compact Disc Technology  Information is stored digitally in the form of microscopic pits on the surface of a reflective metallic layer (“Compact Disc”)  Polycarbonate and Acrylic plastic are used to protect the information storage layer (“Compact Disc) (Brian Marshall “How CDs Work”)

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Information Translation  A laser from the hardware system permeates the polycarbonate substrate and reflects off of the Aluminum layer (Pohlman)  Pits and lands on this layer change the direction of the reflected light and is translated into binary code (“Compact Disc”)

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Ken Pohlman “Compact Disc” Operating Principles of an Audio CD

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Problem Surface Damage Causes If the surface of the CD is scratched or has any kinds of displacement, the laser is not reflected properly Record-Producer.com “How Do CDs Work”

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Problem Statement  Because correct reflection of the laser beam is essential, any surface imperfections may result in an information misread.  Though CDs have error correction for small imperfections, deep or bunched scratches may create data error (Byers).  Polycarbonate is easy to scratch and also subject to crazing which reduces the optical clarity of the material (Ranky).  By increasing the robustness of CDs and simultaneously reducing the frequency of scratches, this everyday technology can be made more reliable.

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Design Alternatives  We considered four different methods of reducing the frequency of error in CDs 1.New Hardware Reading System

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New Hardware Reading System  Increasing CDs spectrum of error correction would allow scratched CDs to still be read  Damage could still occur to the information layer  This would require and entire revamping of the CD economy and would also be very costly

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Design Alternatives  We considered four different methods of reducing the frequency of error in CDs 1.New Hardware Reading System 2.Filler Method

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Filler Method  This method seals the space created by a scratch by replacing the polycarbonate plastic layer (Mount)  The hardware reads through the filler as if it is the polycarbonate plastic layer (Mount)  A permanent, applied version of this existing solution is feasible  Presents too much room for error in consumer application and is also inconvenient

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Design Alternatives  We considered four different methods of reducing the frequency of error in CDs 1.New Hardware Reading System 2.Filler Method 3.Protective Coating

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Design Alternatives  We considered four different methods of reducing the frequency of error in CDs 1.New Hardware Reading System 2.Filler Method 3.Protective Coating 4.Altering the Material Composition

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Altering the Material Composition  Because the polycarbonate layer is prone to damage, replacing this plastic with a more durable material would reduce the frequency of scratches making disc errors less common

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Constraints in Choosing a Material  Aimed to create a new CD compatible with current hardware systems  Must be transparent within a range of 320 to 380 nanometers (Wochele)  Should not compromise any characteristics of current CDs such as temperature limits

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Nanotechnology  One of the most promising avenues for technological advancements  Applies familiar chemical and mechanical principles to unfamiliar applications Chemical reactions are hard to direct, but molecular manufacturing of nanotechnology allows molecules to be binded at specific sites (Eric Drexler “Nanotechnology”)

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Polymer Nanocomposites  Materials produced by introducing nanoparticulates also called fillers into a sample material called the matrix  Polymer nanocomposites are composed of a polymer matrix with a filler measuring no more than 100 nm in at least one dimension  Adding these fillers can drastically enhance properties of the composite (Schadler “ Polymer Nanocomposites: A Small Part of the Story ” ) (“Polymers and Colloids”)

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Polymer Nanocomposites, cont.  Low volume additions of nanoparticulates (1-5%) can provide extensive property enhancements (Schadler)  Because the nanoparticulates have a higher surface area to volume ratio, the density of the protective plastic will increase making it harder to scratch (Centre National De La Recherche Scientifique)

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Efficiency  Nanocomposites can have volume percentages as low as 5 volume % (Schadler) Micrometer-sized filler particles result in a 60 volume % (Schadler) Less material required Nanocomposites are able to do the work of a micrometer-sized filler at a lower volume percent due to their much greater surface area  One undisclosed company reported saving 7% on production costs due to weigh reduction and fuel savings (Puls) Fuel savings in both transportation and production.

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Overview  CDs are the most common source of data storage world wide, but are easily damaged resulting in loss of information  By enhancing the polycarbonate plastic with a more durable nanoparticulate material, the technology will be more reliable  Though the material may potentially cost more, this difference may be offset by decreases in production cost  Design could potentially be applicable to higher density information storage such as DVDs

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Any Questions?

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References Byers, Fred R. Care and Handling of CDs and DVDs: A Guide for Librarians and Archivists. October Copublished by Council on Library and Information Resources and National Institute of Standards and Technology. Centre National De La Recherche Scientifique. 15 May “Compact Disc.” Encyclopedia Britannica Encyclopedia Britannica Online. 29 April CERAM Research Ltd., "Silica - Silicon Dioxide." azom.com The A to Z of Materials AZoM. 7 May Drexler, Eric. “Nanotechnology.” 10 April Access Science McGraw-Hill. 29 April “How Do CDs Work?” AudioMasterclass. 4 March Marshall, Brian. “How CDs Work.” 01 April Howstuffworks. 07 March Mount, Ian. “When Your CD is Skipping.” 19 July Wallstreet Journal. New York, NY. 10 March 2007.